CNN  — 

The US has recently begun seeing “disturbing” trendlines in China’s support for Russia’s military and there are signs that Beijing wants to “creep up to the line” of providing lethal military aid to Russia without getting caught, US officials familiar with the intelligence told CNN.

The officials would not describe in detail what intelligence the US has seen suggesting a recent shift in China’s posture, but said US officials have been concerned enough that they have shared the intelligence with allies and partners at the Munich Security Conference over the last several days.

Secretary of State Antony Blinken raised the issue when he met with his Chinese counterpart, Wang Yi, on Saturday on the sidelines of the conference, officials said.

“The Secretary was quite blunt in warning about the implications and consequences of China providing material support to Russia or assisting Russia with systematic sanctions evasion,” a senior State Department official told reporters.

Vice President Kamala Harris also alluded to China’s support for Russia during her speech in Munich.

“We are also troubled that Beijing has deepened its relationship with Moscow since the war began,” Harris said Saturday. “Looking ahead, any steps by China to provide lethal support to Russia would only reward aggression, continue the killing, and further undermine a rules-based order.”

Officials said the US is seeing China publicly trying to present itself as a proponent of peace – Wang said in Munich on Saturday that Beijing would be introducing a “peace plan” for Ukraine and Russia – and maintain relationships with Europe, while at the same time quietly aiding Russia’s war effort and considering the provision of lethal aid.

“This warfare cannot continue to rage on. We need to think about what efforts we can make to bring this warfare to an end,” Wang said at the conference.

CNN asked European Commission President Ursula von der Leyen on Saturday whether she believed, after hearing Wang’s speech, that China is listening to Europe’s message to not support Russia. “The opposite,” she said, has been seen so far.

“We’ve seen that China and Russia signed an unlimited partnership, and I think we need more proof and more action to see that China is not supporting Russia,” she told CNN. “So far, we see the opposite. And therefore, there is an open question on the table.”

In a clip of an interview with CBS’ “Face the Nation” released on Saturday, Blinken said the US has been monitoring possible increased support for Russia from China “very closely” and has “made very clear” to Beijing the consequences of providing weapons or ammunition to the Kremlin.

“To date, we have seen Chinese companies – and, of course, in China there is really no distinction between private companies and the state – we have seen them provide non-lethal support to … Russia for use in the Ukraine,” Blinken said.

“The concern that we have now is based on information we have that they’re considering providing lethal support. And we’ve made very clear to them that that would cause a serious problem for us and in our relationship,” he added.

As CNN previously reported, the Biden administration last month raised concerns with China about evidence it has suggesting that Chinese companies have sold non-lethal equipment to Russia for use in Ukraine, in an effort to ascertain how much Beijing knows about the transactions, according to two US officials.

That equipment has included items like flak jackets and helmets, multiple sources familiar with US and European intelligence told CNN. But China has stopped short of the more robust military assistance, like lethal weapons systems for use on the battlefield in Ukraine, that Russia has requested because it has not wanted to be seen as a pariah on the world stage, officials said.

But there are signs now that Beijing could now be considering it, the officials said, and Biden administration officials are warning publicly and privately that the US is monitoring closely for any violations of western sanctions prohibiting military support for Russia.

China and Russia publicly declared a “no-limits” friendship just before Russia invaded Ukraine last year, and Wang is set to visit Russia this month, CNN has reported.

This story has been updated with additional details.

CNN’s Nic Robertson, Kylie Atwood, Jennifer Hansler and Aaron Pellish contributed to this report.